A tunnel FET (TFET) has the advantage that the current at power-off time can be extremely reduced as compared to a MOSFET. However, in forming a junction at a drain region by doping, since junction leakage determines a leak level at power-off time, it is not possible to take full advantage of the TFET.
Although several methods for forming a drain junction in order to solve the above problem have been proposed, the existing methods all have a problem that the process becomes complicated.